Television system



A ril 19, 1932.

D. PRINZ TELEVISION SYSTEM Filed April 4, 1931 Fig 1 /T mm:

INVENTOR DIETMC H F filEVZ BY MIN v ATTORNEY Paterited-Apr. 19, 1932 I UNITED STATES PATENT OFFICE DIETRIOH PRINZ OI BERLIN, GERMANY, ASSIGNOB.TO TELEFUNKEN GESELLSC EAIT FUR DRAHTLOSE TELEGBAPHIE M. B. H OIL BERLIN, GERMANY, A CORPORATION OF GERMANY V TELEVISION SYSTEM Application filed Apr-114, 1981, Serial No. 527,689, and in Germany April 8, 1880.

The present invention relates to television systems and, in particular, is directed to the synchronization of the received picture image with the movements of the sub ect 6' located at the point of transmission.

It is known from the prior art that all of-the transmitters and receiver apparatus forming a complete television equipment or installation may be fedfrom one and the 10 same alternating current network.'

It is also known that oscillating or revolving masses involving inertia should be avoided whenever possible. In fact, the moving or migration of the picture point or unit should be insured only by alternating current potentials which are brought to act upon ingrtialess media or means, such as a Braun tu e."

It is also finally known that fractions of a so given frequency may be obtained by what is known as frequency demultiplication. This may be accomplished by causing an alternating current potential of the frequency to be reduced to act upon a so-called relaxation oscillation circuit having approximately the desired lower frequency, as has been described in Zeitschrift fuer Hochfrequenztechnik, vol. 32, page 184, 1928.

It is therefore among the objects of the present invention to provide a method and means whereby a number of television receivers located and connected in the same alternating current network as the transmitter equipment may be synchronized through the use of frequency multiplication and demultiplication devices so that installation of additional synchronizing equipment may be avoided.

' Still other and further objects of the invention will become apparent from a consideration of the following specification and claim when read in connection with the accompanying drawings, wherein:

Fig. 1 illustrates a conventional means for frequency demultiplication; and,

Fig. 2 illustrates a receiving means for pictures wherein the alternating current supply line is utilized for synchronizing purposes.

For the purpose of frequency demultiplication, recourse is had to a system of the type shown schematically by Fig. 1 of the drawings, wherein N is a gaseous-discharge lamp, E a direct current source of approximately 200 volts, for example, arranged in series the resistance R there will then flow an alternating current which is a submultiple of the supply alternating current potential, independently of the frequency of the relaxation oscillations which are governed by C, R, W and E.

According to the present invention, these well-known arrangements are combined in the following fashion:

The televisor receiver is connected with the same alternating current line as the trans- 7 mitter, that is, for example, the usual 50 or 60 cycle alternating current line. The frequency required for causing changes or shifts of line, for instance, of 12.5 pictures per second, is insured by demultiplication of the alternating current. In the instance here chosen, and for the purpose of illustration assummg the input is a 50 cycle alternating current, the frequency should be reduced to onefourth. For this purpose the 50-cycle alternating current potential is applied to a relaxation wave (dynatron, glow-discharge or gaseous-discharge lamp circuit arrangement) the frequency of which amounts to around 12.5 cycles per second. Upon closer consideration it will be seen that this frequency must lie between 50/4=12.5- and 50/3=16.66 cycles per second. Such constancy or nonvariability is readily attainable in practice. Generally speaking, the frequency of the relaxation wave must range between N/k and N/k 1, if frequency N is to be changed into frequency N/k, where N is the frequency in the supply line and 7c is a constant and equal to the ratio of the supply line frequency to the number of complete pictures reproduced per second.

The second frequency which is required for scanning the picture in the difierent lines which may be assumed for illustration purposes as 30 lines per picture, or, in other words 30 12.5=3 5 picture lines per second, may be obtained by frequency multi lication of the picture frequency or some ot er subdivisional frequency of the supply line fre uency, for instance, cycles per second, by t e use of well-known methods.

The production of the line frequency as an overtone of the picture frequency will also be found advantageous when no means are provided with the end of insuring freuency constancy by the supply network. In t is case the relationship between picture frequency and line frequency also remains constant in the presence of fluctuations of the supply-line frequency, since it will be seen that, similarly as in working with the Nipkow disk, in the presence of a fluctuation in the frequency, only the picture as a whole will be caused to shift, while in the presence of independent variations of the picture frequency and line frequency distortions would be occasioned.

An arrangement incorporating thebasic idea herein disclosed is shown in Fig. 2 where incoming signals are received on the aerial A and then suitably amplified by amplifier V by way of which the radio frequency intensity-modulated waves are supplied to the cathode-anode circuit G of a Braun tube image reproducer T. From the alternating current supply network W oscillations are supplied in the frequency-multiplication circuit F indicated by two valves D to the air of plates P In a similar manner oscillations of a lower frequency are fed to the pair of plates P, by the aid of the gaseous-discharge tube N, condenser C and resistance R by way of the demultiplier circuit.

Having now described my invention, what I claim and desire to secure by Letters Patent is the following:

' In a television system, a cathode rav image recreating device, means for controlling the intensity of said cathode ray for image reproduction in accordance with received signalling impulses, a local source of alternating current of a frequency substantially identical with a corresponding local source at the point of transmission, a glow discharge fre- .quency reducing means energized from said local source for producing alternating current im lses of a frequency less than the source requency to control the projection path of said ray in one direction for s nchronizing the movement thereon, and requency multiplying means also energized from said local source for producing alternating current impulses of a frequency greater than the source frequency to control the pro ection path of said cathode ray in a second direction for synchronizing the movement thereof along a path transverse to the first path of synchronized movement.

DIETRICH PRINZ. 

